This invention relates to a cavity resonator having an adjustably tunable resonant frequency, and is especially suitable for use as a cavity resonator in a multi-cavity type klystron. A multi-cavity klystron widely in use as a final stage amplifier tube in various types of transmitters, especially in a high power transmitter, generally has a tuning frequency range of several percent to several tens of percent of the particular midfrequency value.
Tuning systems for cavity resonators are largely classified into three types, one being a system of varying principally an inductance by movement of a side wall of the cavity (abbreviated as L-tuning), another being a system of varying principally a capacitance of the cavity by moving a tuning plate provided in the vicinity of a gap space between drift tubes within the cavity (C-tuning), and the other being a system which combines the aforementioned two systems (L/C-tuning).
These three tuning systems have their respective advantageous features, and they are selectively employed in accordance with needs of the particular application. However, it is said that generally the L-tuning system is a system that is stable in performance.